Infertility is a common cause of marital disharmony in Nigeria because of the high premium placed on child bearing. Male factor is a significant contributor and declining male fertility rate has been observed over the past decade. Oxidative stress has been implicated in the aetiology of male infertility. The objective of the study was to compare the serum levels of oxidative stress markers (TAC – Total Antioxidant Capacity, MDA - Malondialdehyde and SOD – Superoxide dismutase) in male partners of fertile and infertile couples. This was a case controlled study carried out over a period of 8 months on male partners of infertile couple. Thirty-six were male partners of fertile couple with normal semen parameters and no history of infertility while 73 were male partners of infertile couple which consists of 28 males with oligospermia, 28 with oligoasthenospermia and 17 with asthenospermia.. Serum markers of oxidative stress (TAC, MDA and SOD) were evaluated and compared among the group. The male partners of infertile couple showed significantly low levels of TAC (P = 0.000), SOD (P = 0.000) and significantly high levels of MDA (P = 0.000) when compared with male partners of fertile couple (750.93±146.37 versus 1269.20±330.79, 11.22±3.33 versus 13.96±1.38 and 2.48±1.20 versus 1.51±0.19). Oxidative stress may be a major contributor to male infertility. Its assay may be of importance in prevention and treatment of male infertility.